Fibroblast Growth Factor-6 (FGF-6)  is a cytokine belonging to the heparin-binding FGF family, and is structurally related to other members of FGF family, particularly FGF-4. In vivo, FGF-6 exhibits an expression profile predominantly restricted tothe myogenic lineage, and it preferentially binds to two of the FGF receptors: FGFR1 and FGFR4. FGF-6 functions in muscle regeneration, myoblast proliferation and migration, and muscle differentiation in a dose-dependent manner. In vivo high concentration of recombinant FGF-6 up-regulates and down-regulates FGFR1 and FGFR4, respectively, as FGFR1 promotes the proliferation while FGFR4 promotes the differentiation in the muscle. Besides its dual function in  muscle regeneration, FGF-6 may act as a regulator of bone metabolism as well.
Recombinant human Fibroblast Growth Factor-6 (rhFGF-6)  produced in E. coli is a single non-glycosylated polypeptide chain containing 169 amino acids. A fully biologically active molecule, rhFGF-6 has a molecular mass of 18.8 kDa analyzed by reducing SDS-PAGE and is obtained by proprietary chromatographic techniques at ExCell Bio.